Polarization beam splitter-polarization rotator structure

Abstract

A polarization beam splitter-polarization rotator-polarization beam combiner optical structure comprising a pair of polarization rotators having a polarization beam splitter associated with the input ends of the two polarization rotators, and a polarization beam combiner associated with output ends of the two polarization rotators, and a method of purifying a light signal comprising TE and TM modes by disassociating the primary TE and TM modes from first order splitter and rotation error components.

1. An optical structure, comprising:
 a polarization beam splitter comprising a first splitter waveguide having an input end and an output end, and a second splitter waveguide having an output end; 
 a polarization rotator system comprising a first polarization rotator having an input end and an output end and a second polarization rotator having an input end and an output end; 
 a polarization beam combiner comprising a first combiner waveguide having an input end and an output end, and a second combiner waveguide having an input end and an output end; 
 a first optical path including the output end of the first splitter waveguide, the input end of the first polarization rotator, the output end of the first polarization rotator, and the input end of the first combiner waveguide, the first optical path being configured such that first light propagates along the first optical path from the output of the first splitter waveguide to the input end of the first combiner waveguide through the first polarization rotator; and 
 a second optical path including the output end of the second splitter waveguide, the input end of the second polarization rotator, the output end of the second polarization rotator, and the input end of the second combiner waveguide, the second optical path being configured such that second light propagates along the second optical path from the output of the first splitter waveguide to the input end of the second combiner waveguide through the second polarization rotator, wherein the first polarization rotator is spaced from the second optical path and the second polarization rotator is spaced from the first optical path. 
 
   
   
     2. The optical structure of  claim 1  wherein the first splitter waveguide is operatively connected to the first polarization rotator via a first splitter connector waveguide and the second splitter waveguide is operatively connected to the second polarization rotator via a second splitter connector waveguide. 
   
   
     3. The optical structure of  claim 1  wherein the first combiner waveguide is operatively connected to the first polarization rotator via a first combiner connector waveguide, and the second combiner waveguide is operatively connected to the second polarization rotator via a second combiner connector waveguide. 
   
   
     4. The optical structure of  claim 1  wherein the first splitter waveguide supports the TM mode and the second splitter waveguide supports the TE mode. 
   
   
     5. The optical structure of  claim 1  wherein the first splitter waveguide supports the TE mode and the second splitter waveguide supports the TM mode. 
   
   
     6. The optical structure of  claim 1  wherein the first polarization rotator converts TM mode to TE mode and the second polarization rotator converts TE mode to TM mode. 
   
   
     7. The optical structure of  claim 1  wherein the first polarization rotator converts TE mode to TM mode and the second polarization rotator converts TM mode to TE mode. 
   
   
     8. The optical structure of  claim 1  wherein the TM mode and TE mode are combined into the second combiner waveguide. 
   
   
     9. The optical structure of  claim 8  wherein the first order error modes are combined into the first combiner waveguide. 
   
   
     10. The optical structure of  claim 1  wherein the TM mode and TE mode are combined into the first combiner waveguide. 
   
   
     11. The optical structure of  claim 10  wherein the first order error modes are combined into the second combiner waveguide. 
   
   
     12. The optical structure of  claim 1  comprising at least one additional optical element. 
   
   
     13. The optical structure of  claim 12  wherein the at least one additional optical element is a filter, polarizer, waveguide, reflector, coupler, interconnect, phase modulator, intensity modulator, frequency shifter transducer, oscillator, power splitter, resonator or photodetector. 
   
   
     14. An optical structure, comprising:
 a polarization beam splitter comprising a first splitter waveguide having an input end and an output end, and a second splitter waveguide having an output end; 
 a polarization rotator system comprising a first polarization rotator having an input end and an output end and a second polarization rotator having an input end and an output end; and 
 a polarization beam combiner comprising a first combiner waveguide having an input end and an output end, and a second combiner waveguide having an input end and an output end, 
 wherein the output end of the first splitter waveguide, is operatively connected to the input end of the first polarization rotator, and the output end of the first polarization rotator is operatively connected to the input end of the first combiner waveguide, 
 wherein the output end of the second splitter waveguide is operatively connected to the input end of the second polarization rotator, and the output end of the second polarization rotator is operatively connected to the input end of the second combiner waveguide, and 
 the first polarization rotator converts TM mode to TE mode and the second polarization rotator converts TE mode to TM mode. 
 
   
   
     15. An optical structure, comprising:
 a polarization beam splitter comprising a first splitter waveguide having an input end and an output end, and a second splitter waveguide having an output end; 
 a polarization rotator system comprising a first polarization rotator having an input end and an output end and a second polarization rotator having an input end and an output end; and 
 a polarization beam combiner comprising a first combiner waveguide having an input end and an output end, and a second combiner waveguide having an input end and an output end, 
 wherein the output end of the first splitter waveguide is operatively connected to the input end of the first polarization rotator, and the output end of the first polarization rotator is operatively connected to the input end of the first combiner waveguide, 
 wherein the output end of the second splitter waveguide, is operatively connected to the input end of the second polarization rotator, and the output end of the second polarization rotator is operatively connected to the input end of the second combiner waveguide, and 
 the first polarization rotator converts TE mode to TM mode and the second polarization rotator converts TM mode to TE mode. 
 
   
   
     16. An optical structure, comprising:
 a polarization beam splitter comprising a first splitter waveguide having an input end and an output end, and a second splitter waveguide having an output end; 
 a polarization rotator system comprising a first polarization rotator having an input end and an output end and a second polarization rotator having an input end and an output end; and 
 a polarization beam combiner comprising a first combiner waveguide having an input end and an output end, and a second combiner waveguide having an input end and an output end, 
 wherein the output end of the first splitter waveguide, is operatively connected to the input end of the first polarization rotator, and the output end of the first polarization rotator is operatively connected to the input end of the first combiner waveguide, 
 wherein the output end of the second splitter waveguide is operatively connected to the input end of the second polarization rotator, and the output end of the second polarization rotator is operatively connected to the input end of the second combiner waveguide, and 
 the first order error modes are combined into the first combiner waveguide. 
 
   
   
     17. An optical structure, comprising:
 a polarization beam splitter comprising a first splitter waveguide having an input end and an output end, and a second splitter waveguide having an output end; 
 a polarization rotator system comprising a first polarization rotator having an input end and an output end and a second polarization rotator having an input end and an output end; and 
 a polarization beam combiner comprising a first combiner waveguide having an input end and an output end, and a second combiner waveguide having an input end and an output end, 
 wherein the output end of the first splitter waveguide, is operatively connected to the input end of the first polarization rotator, and the output end of the first polarization rotator is operatively connected to the input end of the first combiner waveguide, 
 wherein the output end of the second splitter waveguide, is operatively connected to the input end of the second polarization rotator, and the output end of the second polarization rotator is operatively connected to the input end of the second combiner waveguide, and 
 the first order error modes are combined into the second combiner waveguide.